Of the 50 mass shootings (defined as “three or more killings in a single incident”) that happened in 21 states, 14 incidents ended with the exchange of gunfire between the shooters and law enforcement, 13 shooters committed suicide, 11 shooters were killed by police, 18 shooters were apprehended by police, and 8 shooters were stopped by citizens.

“Armed and unarmed citizens engaged the shooter in 10 incidents,” the report concludes. “They safely and successfully ended the shootings in eight of those incidents. Their selﬂess actions likely saved many lives. The enhanced threat posed by active shooters and the swiftness with which active shooter incidents unfold support the importance of preparation by law enforcement officers and citizens alike.”